What is sarcoidosis?
Sarcoidosis is an inflammatory disease that affects one or more organs but most commonly affects the lungs and lymph glands. As a result of the inflammation, abnormal lumps or nodules (called granulomas) form in one or more organs of the body. These granulomas may change the normal structure and possibly the function of the affected organ(s).
How does the condition progress?
Although no one can predict how sarcoidosis will progress in an individual patient, some clues as to disease course can be gained from patient symptoms, findings from physical and laboratory studies, and patient race. For example, a sudden onset of general symptoms--such as weight loss, fatigue, fever, or just an overall feeling of ill health--usually means that the course of sarcoidosis will be relatively short and mild in severity. Symptoms of shortness of breath and some types of skin involvement mean that sarcoidosis will be more long-lasting and severe.
In Caucasians, the disease often appears suddenly, which usually indicates a more mild form of the disease that is of short duration. African-Americans and Puerto Ricans, on the other hand, tend to develop the more long-term and severe form of the disease.
In the United States, the lungs are often the most common site of initial symptoms for those who experience a gradual onset of their long-term disease. Lung symptoms are common in African-Americans, Puerto Ricans, and Scandinavians. Persistent dry cough, fatigue, and shortness of breath are the most common initial lung-related complaints.
What systems of the body are affected by sarcoidosis?
Beyond the lungs and lymph glands, the body organs or systems affected by sarcoidosis that are associated with the most noticeable symptoms are the skin, eyes, musculoskeletal system, nervous system, heart, liver, and kidneys, in this order. Patients can have symptoms related to the specific organ affected, or can have general symptoms, or can have no symptoms whatsoever (for example, laboratory findings frequently show the liver to be affected by sarcoidosis, yet patients generally do not report any liver-related symptoms).
An individual patient's symptoms can also vary according to how long the illness has been under way, where granulomas are forming, how much tissue has become affected, and whether granuloma formation is still active or has developed into scar.
Some patients who experience sudden onset of disease have Lofgren’s syndrome, a form of sarcoidosis that affects the lymph nodes and is accompanied by a skin condition that produces red nodules under the skin, as well as fever and arthritis pain. Patients with Lofgren’s syndrome usually can expect a good outcome; the disease goes away on its own in 85% to 90% of people.
How sarcoidosis progresses: What happens at the tissue level
At the tissue or cellular level, sarcoidosis disease progression can be divided into three phases:
- The first change that is seen is inflammation.
- In the second phase, granulomas form. Granulomas are masses or nodules of chronically inflamed tissue and are the classic sign of sarcoidosis Granulomas are the body’s attempt to wall off or isolate organisms and other foreign particles that are difficult for the immune system to eradicate or dispose of.
- In the third phase, fibrosis (scarring) of tissues or organs occurs. If scarring is extensive in a vital organ, sarcoidosis is sometimes fatal.
In some people, the disease advances from one phase to the next in the tissues of the organ affected. In others, the different phases of tissue changes take place within the same organ at the same time. In many patients with sarcoidosis, the granulomas go away on their own in 2 to 3 years without the patient knowing or doing anything about them. In others, the granulomas progress to irreversible fibrosis. The immune system changes that allow one person’s disease to progress while another person’s disease resolves are not well understood and continue to be investigated.
Does sarcoidosis run in families?
While the latest research does appear to indicate a genetic susceptibility to the disease, more research is needed to clearly identify and confirm the genes involved. However, numerous reports have revealed racial/ethnic and family-line occurrences, including the following:
- Irish immigrants in London have a three-fold likelihood of developing sarcoidosis compared with native Londoners.
- Natives of Martinique living in France have an eight-fold higher chance of developing the disease compared with the native French population.
- African-Americans face a 4 to 17 times greater risk of the disease compared with Caucasians.
- Within individual families, the presence of the disease in a first- or second-degree relative increases the risk by nearly five-fold.
Still other types of disease clusters have been identified, including seasonal and occupational clustering. Researchers in Greece, Spain, and Japan have reported a clustering of diagnoses of sarcoidosis in the months of March to May, April to June, and June to July. In the United States, a higher percentage of cases of sarcoidosis have been reported in health care workers, naval aircraft servicemen, and firefighters.
What are symptoms of sarcoidosis when it affects the lungs?
The lungs are affected in more than 90% of individuals with sarcoidosis. Even in individuals whose disease primarily affects other organs, the lungs are usually affected as well. Shortness of breath, cough, and chest discomfort are the most common lung-related symptoms. Patients may be free of chest symptoms despite an abnormal chest x-ray and biopsy-proven sarcoidosis. Occasionally, patients have chest pain – which is usually described as a vague tightness of the chest – but sometimes the pain can be severe and similar to cardiac pain.
It's thought that sarcoidosis of the lungs begins with alveolitis. Alveolitis is inflammation of the alveoli, which are the tiny sac-like air spaces in the lungs where carbon dioxide and oxygen are exchanged. Alveolitis either clears up by itself or progresses to granuloma formation. Samples of lung tissue may show the presence of granulomas.
Granulomas in the lungs can lead to narrowing of the airways, enlargement of lymph nodes in the chest, and inflammation and scarring (fibrosis) of lung tissue. The scarring causes the lung tissue to stiffen and destroys the air sacs, making it more difficult to breathe.
What are symptoms of sarcoidosis when it affects the skin?
About 25% of patients with sarcoidosis develop at least one skin symptom. Tender, painful, reddish bumps or patches on the skin (erythema nodosum) – usually on the shins – accompanied by swollen and painful joints are common. Lupus pernio (a chronic skin condition marked by purple-colored lesions on the cheeks, lips, nose, and ears) is common in older African-Americans and West Indian women with long-standing disease.
Other skin signs in patients with long-term disease include plaques, patches (with and without color), nodules, and hair loss. The range in appearance of skin-related lesions – from subtle, painless rashes to deep scars – often correlates with the severity of sarcoidosis involving the internal organs. The skin changes can be visible or under the skin.
What are symptoms of sarcoidosis when it affects the eyes?
About 25% of people with sarcoidosis have eye symptoms. Inflammation of almost any part of the eye can occur--this includes the membranes of the eyelids, cornea, outer coat of the eyeball (sclera), iris, retina, and lens. The most common eye-related symptom is acute anterior uveitis (inflammation of a layer of the eye), which results in the rapid onset of blurred vision, teary eyes, and light sensitivity. In long-standing disease, glaucoma, cataracts, and blindness can occur. Dry eyes are very frequent in long-standing sarcoidosis, even when there is no remaining inflammation. They can be treated with eye drops.
Because some sarcoid-related eye problems do not cause symptoms, it is important that all patients with sarcoidosis have at least yearly appointments with an ophthalmologist.
What are symptoms of sarcoidosis when it affects the musculoskeletal system?
Approximately 10% to 15% of patients may have bone and muscle symptoms, resulting in arthritis, changes in bone structure, or muscle discomfort and pain.
What are symptoms of sarcoidosis when it affects the nervous system?
Neurologic disease occurs in 5% to 10% of patients, often without symptoms in other organs. Symptoms of neurologic involvement include headaches, meningitis, seizures, and nerve tissue degeneration or inflammation – which results in muscle weakness, pain, and numbing or tingling sensations in the face, arms, and legs.
A more recently-discovered type of neurosarcoidosis is small fiber neuropathy (SFN). SFN causes a loss of some types of nerve fibers and requires specialized testing to identify it. Patients with SFN often note burning pain, sensitivity to touch, palpitations, sweating, flushing, light-headedness, gastrointestinal difficulties, and sexual dysfunction.
What are symptoms of sarcoidosis when it affects the heart?
Heart disease is present in 28% of patients with sarcoidosis, although only about 5% of patients report having any heart-related symptoms. Any part of the heart's structure may be affected by granuloma formation. The most frequently diagnosed heart problems include chest pain, cor pulmonale (an enlargement of the right side of the heart that results from disease in the lungs or its blood vessels), cardiomyopathy (disease of the heart muscle itself), and abnormalities in the heart's electrical system, which can result in heart block, dysrhythmias, and sudden death. It is vital to notify your doctor immediately if you start to develop palpitations or dizzy spells, as this may be the first sign of cardiac involvement. Everyone diagnosed with sarcoidosis should have a baseline EKG (heart tracing).
What are symptoms of sarcoidosis when it affects the liver?
Granulomas are present in the liver in 50% to 80% of patients with sarcoidosis. However, patients usually do not notice the symptoms due to liver involvement. Rarely, liver disease can progress to hypertension in the liver (called portal hypertension) or cirrhosis (a disease causing widespread disruption of liver function).
What are symptoms of sarcoidosis when it affects the renal and endocrine system?
Abnormalities can occur in the way the body handles calcium. For example, hypercalcemia (an excess of calcium in the blood) occurs in 2% to 10% of patients. Hypercalciuria (an excess amount of calcium in the urine) occurs in up to 21% of patients. Kidney stone formation, damage to the structure of the kidney itself, and kidney failure may also occur. Another endocrine abnormality seen in sarcoidosis is hypopituitarism. The pituitary gland is at the base of the brain and secretes eight different hormones. The signs and symptoms of hypopituitarism vary, depending on which hormones are undersecreted. Occasionally, there is decreased secretion of all the hormones and this is called panhypopituitarism. Diabetes can occur as a complication of sarcoidosis therapy.
What are symptoms of sarcoidosis when it affects the reproductive system?
Sarcoidosis can affect the male reproductive system, particularly the testes, and may cause male infertility and erectile dysfunction. The disease rarely affects the female reproductive system. Sarcoidosis does not increase the incidence of fetal or maternal complications during pregnancy, unless it has caused severe impairment of the heart or lungs. However, the disease may worsen after childbirth.
What are symptoms of sarcoidosis when it affects organs such as the spleen?
Cytopenias (deficiencies in the amounts of certain blood cells) are the most common "miscellaneous" symptom. Involvement of the spleen or bone marrow may lead to anemia and other blood abnormalities. These conditions usually are not of clinical significance. Bone thinning (osteopenia) is also common in sarcoidosis, as a result of the disease or as a side effect of prednisone therapy.
Some very common conditions seen in those with sarcoidosis are depression, fatigue, and obstructive sleep apnea. Often, these are the most significant problems affecting the quality of life. Depression may occur in up to 2/3 of patients with sarcoidosis, and can cause much of the fatigue that people with sarcoidosis experience. Sleep apnea is suspected in individuals with fatigue, excessive daytime sleepiness, or an unrefreshed feeling on awakening in the morning. Most individuals snore, or experience episodes of choking or gasping at night. Sarcoidosis of the sinuses or nose, weight gain from steroids, and lupus pernio are three factors that increase the chances for obstructive sleep apnea. If your doctor suspects sleep apnea, it may be diagnosed by overnight monitoring in a sleep lab. This sleep test is called a polysomnogram.
What causes sarcoidosis?
The exact cause of sarcoidosis is not known. The disease can appear suddenly and then disappear, or it can develop gradually and produce symptoms that come and go for a lifetime.
Researchers believe that the disease is caused by an abnormal immune response. (The body’s defense system does not react as it should to a foreign substance "intruder.") In a healthy person, inflammation occurs as the cells of the body’s immune system come together to fight the intruder at an organ or tissue site. In a person with sarcoidosis, however, cells that come to fight end up clumping together into small lumps called granulomas.
It’s still uncertain which foreign substance "triggers" the body’s abnormal response. Some researchers suggest that fungi, viruses, or bacteria are likely triggers. In fact, cases of sarcoidosis have occurred in groups of people who had close contact with each other, as well as in recipients of heart, lung and bone marrow transplants. But, so far, no data have been able to convincingly and consistently establish this "infectious" connection as the cause of the disease. However, some types of bacteria have recently emerged as possible candidates and continue to be closely studied.
What are the symptoms of sarcoidosis?
The symptoms of sarcoidosis can vary greatly from individual to individual, and depend on which tissues and organs are affected. In some people, symptoms may begin suddenly and/or severely and subside in a short period of time.
Others may have no outward symptoms at all, even though organs are affected. Still others may have symptoms that appear slowly and subtly, but last or recur over a long time span.
Most common initial symptoms:
- Shortness of breath (dyspnea).
- Cough that won’t go away.
- Reddish bumps or patches on the skin or under the skin.
- Enlarged lymph glands in the chest and around the lungs that produces cough and shortness of breath.
- Fever, weight loss, fatigue, night sweats, general feeling of ill health.
Other disease characteristics include:
- Red and teary eyes or blurred vision.
- Swollen and painful joints.
- Enlarged lymph glands in the neck, armpits and groin.
- Nasal stuffiness and hoarse voice.
- Pain in the hands, feet, or other bony areas due to the formation of cysts (an abnormal sac-like growth) in bones.
- Kidney stone formation.
- Development of abnormal or missed beats (arrhythmias), inflammation of the covering of the heart (pericarditis), or heart failure
- Nervous system effects include hearing loss, meningitis, seizures or psychiatric disorders (for example, dementia, depression, psychosis).